Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

MFC r249526, r249600:
DTrace: NFS translators should be split into client/server pieces

Merge change from illumos:

1731 DTrace NFS translators should be split into client/server pieces

Include Changes from OpenSolaris:
PSARC 2008/050 DTrace NFS v3 Provider
6696397 NFS v3 provider reports all UDP clients as 0.0.0.0
6711844 assert: vp-->v_shrlocks

Illumos Revision: 13523:6763769941d2

This code seems to be currently unused on FreeBSD.

Reference:
https://www.illumos.org/issues/1731

Obtained from: Illumos

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Add the DTrace libraries and D library scripts.